This invention relates in general to an apparatus for manufacturing articles, and in particular, to the molding of materials.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to an apparatus for unloading molded articles which are manufactured by a molding machine.
Many articles are manufactured by being molded into a desired configuration from an elastomeric material and the like. One type of molding is known in the art as compression molding, by which a blank or "prep" is heated into a fluent state and is compressively caused to assume a shape defined by a die cavity. An example of the employment of compression molding as a manufacturing technique exists in the oil seal industry. One common oil and grease seal manufactured through a molding process comprises a seal body having one or more sealing lips fabricated from a natural or synthetic elastomer, which is bonded to or otherwise cooperates with at least a part of a stiff casing or other structural member. The casing, stamping, or stiffener is utilized to provide rigid mounting of the seal, while the elastomeric seal body in use engages one or more members to provide fluid retention and the like.
It is common practice to manufacture such oil seal articles by compressive molding, because of the relative economy and simplicity of the process. Compression molding permits large numbers of articles to be formed simultaneously in multiple cavity molds in a single cycle of the molding press. It is possible to produce 24, 36, 48 or other large number of parts during one heat cycle of operation of the machine. To accomplish the simultaneous molding of a large number of articles, compression molding machines are generally physically large and include a plurality of cooperable plates and die components. A molding plate possesses a substantial surface area to accomodate the plurality of molding stations required to produce a multiple output. Accordingly, physical access to the finished oil seals formed at each of the molding stations at the conclusion of a molding operation is cumbersome and inconvenient. Because of the large number of articles which are molded at such relatively inaccessible stations, it is inefficient and time consuming for the machine operator to reach and unload the plurality of molded articles by hand at the conclusion of a molding cycle. Manual retrieval is further undesirable, since it is possible that one or more finished parts may be inadvertently left in the molding plate and interfere with the subsequent operation of the press. Physical handling of the finished oil seals after molding is also unsuitable and potentially hazardous, because of the temperature to which the seal is elevated following a molding operation. Often a molded oil seal can attain a temperature in excess of 300.degree. F. following a compression molding operation. Such heated articles require the use of gloves or other protective measures to prevent injuries to the press operator. Thus, one by one manual retrieval of the finished parts is an undesirable technique for unloading molded articles from the molding press.
In the prior art, several automatic retrieval systems have been employed to overcome the inherent problems of manual removal of the molded oil seals. Such automated techniques have relied upon the use of relatively complicated systems, which have not attained an optimum level of efficiency and economy. Prior art unload apparatus tend to subject the molding machine and the molded parts themselves to unnecessary stress and impact. Moreover, conventional unloaders are deficient in attaining a high degree of efficiency of operation in conjunction with the molding apparatus for maximum productivity.